1. Field of the Invention
The present invention relates to an image processing apparatus which performs refocus calculation processing for light field data.
2. Description of the Related Art
Recently, an image capturing apparatus having the following arrangement is proposed in, for example, “Ren. Ng and seven others, ‘Light Field Photography with a Hand-Held Plenoptic Camera’, Stanford Tech Report CTSR 2005-02”. In this image capturing apparatus, each microlens array is arranged in front of a solid-state image sensor for a plurality of pixels to obtain even information in the incident direction of a light beam entering the image sensor. As application purposes of this image capturing apparatus, the following application is conceivable, in addition to generating a normal shot image based on an output signal from each pixel. More specifically, the image capturing apparatus can reconstruct an image by refocus calculation processing using a coefficient (to be referred to as a refocus coefficient hereinafter) which adjusts the focus to a desired focus position in a shot image.
When viewing a refocusable image, the image blurs at a portion which is out of focus, and it is difficult to search for an object the user wants. To solve this problem, Japanese Patent Laid-Open No. 2011-22796 discloses a technique of extracting an object from an image and displaying a refocus image in which the object is in focus.
However, in the conventional technique disclosed in Japanese Patent Laid-Open No. 2011-22796, it is necessary to hold information in shooting as tag data, and calculate a phase difference between a plurality of images corresponding to different viewpoints in order to determine a refocus plane after reconstruction. As a result, the calculation amount becomes large.